1. Field of the Invention
The present disclosure relates to the treatment of opioid-induced constipation (OIC). More particularly, the disclosure invention relates to the use of extract from Aster spp. in the treatment of opioid-induced constipation.
2. Description of Related Art
An opioid, in its widest sense, refers to a compound that binds to opioid receptors, which are distributed widely in the central and peripheral nervous system and the gastrointestinal tract. Opioids may be classified as natural, synthetic, or endogenous opioids. Natural opioids such as codeine and morphine are derived from opiate alkaloids contained in the opium poppy. Synthetic opioids refer to manmade compounds created by chemically modifying the natural opioids (e.g., oxycodone) or synthesized from non-opioid substances (e.g., methadone). Endogenous opioids are naturally produced by the body and include substances such as endorphins.
Opioids are commonly prescribed for their analgesic, or pain-killing, properties. However, opioid use carries several side effects, including drowsiness, nausea, vomiting, slower breathing, and a general depression of the respiratory system. Further, opioids often cause constipation, or more particularly, opioid-induced constipation. Accordingly, additional medicines are often required to be prescribed along with the opioid painkillers that cause the constipation. For example, laxatives and/or cathartics for use in the treatment of ordinary functional constipation are prescribed to treat opioid-induced constipation. A cathartic accelerates defecation, while a laxative eases defecation, usually by softening the stool; some medicines are considered to be both laxatives and cathartics. Although functional constipation and opioid-induced constipation share many signs and symptoms in common, treatments for functional constipation are not always successful in treating opioid-induced constipation. Therefore, targeted treatment for opioid-induced constipation has been pursued.
Oral opioid-receptor antagonists, including naloxone, naltrexone, and nalmefene have been suggested to be potentially helpful in ameliorating opioid effects in the gastrointestinal tract. However, these agents may be of limited use because they also cross the blood-brain barrier and can reverse analgesic effects of opioids, or induce uncomfortable opioid withdrawal symptoms. Methylnaltrexone is a newer agent that blocks peripheral opioid receptor. Therefore, methylnaltrexone may decrease the constipating effects of opioid pain medications in the gastrointestinal tract without affecting analgesia effects in the central nervous system. However, since up to 60 percent of opioid analgesia may be mediated by opioid receptors on peripheral sensory neurons, methylnaltrexone would increase pain under such circumstances.
In view of the foregoing, there exists in the art a need for a novel composition and method that treat opioid-induced constipation.